In a second post, Trump claimed that many people were not interviewed before Comey's draft. He said the investigation was "obviously a fix" and called on the Justice Department to investigate.

On Monday, the FBI released a heavily redacted version of the letter Comey drafted before interviewing Clinton and other key witnesses in the 2016 probe, confirming earlier reports.

In August, Senate Judiciary Committee Chairman Chuck Grassley and Sen. Lindsey Graham released a statement saying Comey had "already decided he would issue a statement exonerating Secretary Clinton" before the FBI had interviewed her.

Chris Swecker, a retired FBI assistant director in the criminal investigative division, told Newsweek at the time that Comey's actions were "so far out of bounds it's not even in the stadium," and that it seemed the former director had "prejudged the investigation."

Comey ultimately concluded that although Clinton had been "extremely careless" by sending top secret information over her private server, she had not committed a criminal act.

Former FBI Director James Comey sworn in to testify at a hearing in Washington Thomson Reuters

In May, Trump fired Comey as the investigation into his campaign's possible ties to Russia intensified.

Throughout his campaign and presidency, Trump has repeatedly accused the FBI, the media, and the government of being part of a "rigged system."

Robert Mueller, the special counsel who is leading the FBI's investigation into Russian election interference, has reportedly expanded the investigation to include determining whether Trump obstructed justice when he fired Comey in May.